JP4071867B2 - Ladle and ladle bottom construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refractory structure at the bottom of a molten metal ladle used during steelmaking and steelmaking, and a method for constructing the furnace.
[0002]
[Prior art]
In recent years, as a method for constructing a ladle bottom, in order to save labor, pouring construction from a brick floor with an irregular refractory is becoming a main component. However, in this casting construction, there are problems such as requiring large facilities such as a kneader and a dryer, taking curing and drying time, and standing up dust during kneading.
[0003]
In addition, as an example of construction using a precast block as well as construction using a casting material, for example, in Japanese Patent Application Laid-Open No. 6-71422, a hot water contact portion is constructed using a precast block, and the others are constructed using castable. In addition, Japanese Utility Model Laid-Open No. 7-6693 discloses that the hot water contact portion is constructed by a precast block, the tuyere side is constructed by brick, and the other portion is constructed by a pouring material.
[0004]
However, also in the above example, the ladle furnace bottom part uses not only the precast block but also the pouring material, so the problem due to the pouring work is not solved. Rather, due to the combination of casting methods, the casting surface of the casting part forms a horizontal smooth surface, and when the molten metal is discharged, a large amount of hot water remains in the bottom of the ladle, causing not only a decrease in yield but also local melting. It becomes easy.
[0005]
Japanese Patent Application Laid-Open No. 57-187163 discloses that a precast block is applied to a laying portion which is a work lining of a bottom portion of a ladle for labor saving. In this case, the lifting jig is embedded in the precast block in advance, and this is handled by using the lifting jig for the drying process at the time of manufacturing the precast block and the subsequent setting of the actual furnace. It is like that. For this reason, since the embedded lifting jig is melted when the actual furnace is used, the molten metal is easily inserted into the precast block, and the structure of the lifting jig embedded portion is significantly weakened when the actual furnace is used. Furthermore, there is a drawback that due to the difference in thermal expansion between the precast block and the lifting jig, an internal crack is generated in the block, resulting in a significant decrease in durability.
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to increase the efficiency of the construction work when laying a precast block at the bottom of a ladle, to eliminate local melting of the laid bottom of the ladle, and to improve its durability.
[0007]
[Means for Solving the Problems]
The present invention, in the furnace bottom portion becomes laying the precast block is divided into at least water per unit and other general bottom part and in ladle was thicker than the general bottom part of the hot water per unit, generally bottom part A molten metal guide groove having a downward slope toward the molten metal outlet is provided.
[0008]
The general floor is preferably divided into 1 to 2 to 4 pieces depending on the size of the construction body. Moreover, the divided hot water contact portion and the general laying portion can be laid in a state of being assembled in advance with a mortar or the like.
[0009]
When applying the precast block to the furnace bottom of a large ladle with a capacity of 1 ton or more, it is divided into at least a hot water hitting part and a general laying part that is other than that, thereby avoiding the enlargement of the casting frame and handling. In addition, it is possible to avoid the difficulty in handling in the drying operation and to prevent an increase in manufacturing cost.
[0010]
The general floor portion is provided with a molten metal guide groove having a downward slope toward the molten metal outlet installation portion. This is to prevent local melt damage due to the molten metal from being easily caused because the molten metal remains as a pool during discharge when the construction thickness of the general floor is constant. Accordingly, the molten metal guiding groove is sufficiently effective if it has a groove shape having a downward slope so as to flow toward the molten metal outlet. The downward inclination is preferably 5 degrees or more with respect to the horizontal plane, and more preferably about 10 to 20 degrees.
[0011]
In addition, a ladle bottom structure with a downward slope of about 5 to 10 degrees toward the molten metal outlet installation part or the molten metal guiding groove is provided so that the molten metal flows toward the outlet. However, it eliminates hot water pools and eliminates local melting damage.
[0012]
In addition, the precast block laying work, which is made by dividing the ladle bottom of the ladle into at least a hot water contact part and a general laying part, opens a handling slit on the working surface side of the general laying part and lifts it to the slit After laying with the jig, the lifting jig is pulled out and the slit is backfilled with the irregular refractory, and the gap between the general laying part, the hot water contact part and the side wall part is filled with the irregular refractory. Thereby, it is possible to obtain a ladle furnace bottom floor structure that does not form the weak part of the precast block.
[0013]
The slit that becomes the hooking part has its opening slightly larger than the shape of the insertion part of the lifting jig, and the internal shape of the insertion is determined by considering the weight of the block and the thickness of the work. The length space and a hooking space in which the hooking member rotates and can be hooked are formed. This slit can be melted or removed by burning at the casting part, and it is filled with sand, water, etc. into wax material, paraffin wax, polystyrene foam, wood, paper, etc. It is formed by embedding the combined molded body and eliminating or burning it out at the drying step, or removing the mold after the general floor block is cured.
[0014]
Moreover, if there is a joint between the precast blocks in the hot water contact portion, it is disadvantageous in terms of durability when using an actual furnace. For this reason, it is desirable that the hot water contact portion where the actual furnace wear is severe be an integral portion having a thicker construction thickness than the general floor portion.
[0015]
The amorphous refractory used for backfilling or filling is preferably the same material as the precast block or a highly durable castable refractory. Moreover, the flow value as fluidity indicating the filling property was measured according to JIS R2512. If this value is 150 mm or more, it indicates a blended state with considerably good filling properties, but it is more preferably 200 mm or more.
[0016]
The precast block has a refractory structure in advance and can be laid in a dry state, so it can be transported with a large lift and set at the bottom of the ladle furnace, allowing it to be used immediately in the actual furnace, greatly shortening the work period and saving labor. Can be achieved even under tight processes when using an actual furnace.
[0017]
As a result, even if a large precast block is used, handling of the block is facilitated by the use of a crane and a lift during the building operation, which not only makes the building more efficient and labor-saving, but also allows only casting. The durability can be improved as compared with the construction.
[0018]
When a precast block is laid on the bottom of the pan furnace, an amorphous refractory such as mortar is filled in the surface, side wall and gap between each block. In this case, if the amount of the amorphous filler used and the amount of added water are large, a drying step is required after setting the precast block. Therefore, it is desirable that these amorphous fillers have as little added moisture as possible, and it is desirable to use a semi-wet or dry product rather than a wet one. Use the one with less usage.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
As the refractory aggregate of the precast block used in the present invention, siliceous materials such as silica, silica sand, electrofused silica, hydrous amorphous silica, anhydrous amorphous silica as an oxide raw material, mullite, bauxite, bang shale, sillimanite, Alumina such as kyanite, sintered alumina, electrofused alumina, calcined alumina, silica-alumina such as rholite, chamotte, porcelain stone, clay, kaolin, bentonite, zirconia such as zircon, zirconia, electrofusion Basic properties such as magnesia, seawater magnesia or synthetic magnesia, natural magnesia, alumina-magnesia spinel, calcium oxide, and chromic substances such as spinel, chromium oxide, and chromite can be used. Silicon carbide, aluminum carbide, zirconium carbide or the like can be used as the carbide raw material. As the nitride material, zirconium nitride, silicon nitride, silicon nitride iron, boron nitride, aluminum nitride, or the like can be used. As raw materials containing carbon, carbonaceous raw materials such as natural graphite such as coke, scale-like graphite, scale-like graphite, and earth-like graphite, artificial graphite, calcined anthracite, coal powder, pitch powder, carbon brick, and electrode scraps can be blended. In addition to the above, it is selected from the group consisting of all refractory raw materials such as borides such as boron carbide, silicides such as silicon and ferrosilicon, and one or more kinds can be used in combination as required.
[0020]
The precast block of the present invention may further use various metal fibers and other fibers such as carbon fiber and SiC fiber as necessary. In addition, antioxidants such as glass, metal powder and metal particles may be added.
[0021]
【Example】
Hereinafter, based on the Example shown to an accompanying drawing, the construction method of the ladle of this invention and its furnace bottom is demonstrated.
[0022]
FIG. 1 shows an example of the bottom structure of a ladle 1 laid separately and viewed from above. FIG. 2 (a) shows an example in which the base laying part 2 and the hot water contact part 3 are divided into two, and the general laying part 2 is provided with a molten metal outlet 4 and has a downward slope toward the outlet 4. A molten metal induction groove 5 is provided. Reference numeral 6 denotes a porous plug hole.
[0023]
Moreover, the same figure (b) shows the example in which the general laying part 2 was divided into two parts, and was divided into three blocks including the hot water contact part 3, and the molten metal guiding groove 5 was joined so as to be continuous between the blocks. ing. As a result, when the actual furnace is used, (a) and (b) in FIG. There is no problem in workability and functionality even if the general floor portion is divided into three or four divisions depending on the overall size. Further, the molten metal guiding groove 5 does not have to be in the position or shape as shown in the figure, and can be provided toward the spout 4 so as to sandwich the porous plug 6 from both sides.
[0024]
FIG. 2 is a cross-sectional view taken along the line II of FIG. 1 (a), in which a molten metal guiding groove 5 is provided in the general floor portion 2 and the bottom thereof is provided with a downward slope 7 so that the molten metal flows toward the spout 4. It is.
[0025]
FIG. 3 is a cross-sectional view taken along the line II-II in FIG. 1 (a) and shows a structure in which the hot water contact portion 3 is made thicker than the general lay portion 2 and laid.
[0026]
FIG. 4 is a modification of FIG. 2, and the surface of the general floor portion 2 is also provided with an inclined portion 8 toward the molten metal guiding groove 5 or the spout 4 so as to flow from both sides, thereby further forming a hot water pool. Can be prevented.
[0027]
FIG. 5 is a perspective view showing an example of a general laying part division body of a precast block. The general laying block 12 is provided with a molten metal guide groove 15 toward the molten metal outlet hole 14, which can help discharge the molten metal from the fitting pouring nozzle and eliminate the hot water pool. 16 is a hole for a porous plug, and 17 is a slit 17 for suspending according to the present invention.
[0028]
FIG. 6 is a view for explaining the slits 17 formed in the general laying block 12 used in the construction of the ladle bottom structure. FIG. 4A is a partial plan view of the general laying block 12, and the slit 17 has a width a and a width b with a margin sufficient to allow the lifting jig to be inserted therethrough. FIG. 7B is a cross-sectional view taken along the line III-III in FIG. The depth c of the slit 17 shown in the figure needs to be made not to be so thin considering the strength when it is lifted, within the limitation of the thickness of the general laying block 12, and the engaging portion space of the lifting jig It is necessary to make the film in consideration of the thickness d at 18 and the shaft portion width b. The engaging portion space 18 is formed so that the engaging portion of the lifting jig can be rotated. The slit 17 including the engaging portion space 18 was obtained by disposing the foamed polystyrene having the shape of the entire slit when casting the general laying block 12 and removing the mold after the general laying block 12 was cured. . As for the installation state of the slit mold, it is possible to embed it in the block, but considering the embedding work at the time of casting and the removing work after curing, the bottoming method as shown in the figure is simple. .
[0029]
FIG. 7 shows the form of the building of the blocks shown in the above figures. FIG. 4A is a state diagram in which the general laying block 12 is suspended, and FIG. 2B is a drawing of the lifting jig 19 used when lifting the general laying block 12 in FIG. It is an enlarged view. In these drawings, the lifting jig 19 inserted in the slit 17 of the general laying block 12 rotates in the hooking space 18 shown in FIG. The shaft 21 has a length that extends out of the length c, and a hook member 24 such as a ring shape, a T shape, or a hook shape is provided at the tip of the shaft 21. It has a structure that can be done.
[0030]
The lifting method of the block is that the lifting jig 19 is inserted into the slit 17 portion of the block 12 and lowered to a depth of (c + d), and then the lifting jig is rotated about ¼, thereby lifting the lifting jig. By lifting the block, the block can be lifted. By inserting the lifting jig 19 into each of the three slits 17 in FIG. 7 (a), the general laying block 12 can be lifted using the lifting device 22 using a crane or the like (not shown). In this way, after the block 12 is set at a predetermined position, the lifting jig 19 is removed from the slit 17, and the slit 17 is filled with an irregular refractory.
[0031]
In the method in which the lifting jig embedded in the conventional precast block cannot be completely removed after the precast block is set, due to the difference in thermal expansion between the precast block and the lifting jig, Internal cracks were caused, leading to a significant decrease in service life. On the other hand, according to the construction method of installing the precast block of the present invention, since the construction can be performed without leaving the lifting jig in the furnace floor portion, the durability is improved with no wear due to molten metal intrusion.
[0032]
【The invention's effect】
By implementing the present invention, the following effects can be obtained.
[0033]
(1) Not only the construction method is easy by using a split structure of precast blocks, but there is no dust and there is no blending loss during construction, so the working environment is good.
[0034]
(2) By providing a molten metal guiding groove having a downward slope toward the molten metal pouring outlet of the general laying part, local melting loss was reduced and the service life of the ladle furnace laying part was extended. Moreover, the effect of extending the service life of the ladle furnace can be obtained by providing a gentle downward slope toward the molten metal outlet or the molten metal guiding groove on the bottom of the furnace.
[0035]
(3) Since the precast block is simply lifted and set by a crane or the like, the construction efficiency and construction period at the construction site can be greatly reduced.
[0036]
(4) Since a precast block is used, it is possible to select a material having a fire resistance, corrosion resistance, spalling resistance and other characteristics according to the actual furnace usage conditions and the construction thickness regardless of the construction conditions. This prolongs the durability of the refractory.
[0037]
(5) Since the lifting jig can be constructed without remaining on the precast block, there is no wear due to molten metal intrusion, and there is no occurrence of cracks due to a difference in thermal expansion from the lifting jig, thereby improving durability.
[Brief description of the drawings]
FIG. 1 shows an example of a bottom ladle structure of a ladle laid separately as viewed from above. (A) shows an example in which the general floor portion and the hot water contact portion are divided into two parts, and (B) shows an example in which the general floor portion is divided into two parts and includes the hot water contact portion.
2 is a cross-sectional view taken along the line II of FIG.
3 is a cross-sectional view taken along the line II-II in FIG.
4 shows a modification of FIG.
FIG. 5 shows an example of a general laying division of a precast block.
FIG. 6 is a view for explaining slits formed in a general laying block used for building a ladle bottom structure.
FIG. 7 shows a construction of a furnace using a block.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ladle 2 General floor part 3 Hot water contact part 4 Molten pouring hole 5 Molten induction groove 6 Porous plug hole 7 Down inclination 8 Inclining part 12 General floor block 14 Molten pouring hole 15 Molten induction groove 16 Porous plug hole 17 Slit 18 Hanging part space 19 Lifting jig 20 Hanging part 21 Shaft member 22 Lifting device 23 Wire 24 Hanging member 25 Hanging member

Claims (3)

The furnace bottom portion becomes laying the precast block is divided into at least water per unit and other general bottom part, and in ladle was thicker than the general bottom part of the hot water per unit, the melt spout generally bottom part A ladle having a molten metal guide groove having a downward slope toward the top.   The ladle according to claim 1, wherein the general floor portion is provided with a downward slope toward the molten metal outlet or the molten metal guiding groove. In ladle furnace bottom insole construction method of laying the precast blocks made by dividing into at least water per unit and other general bottom part in the furnace bottom, molten metal guide groove having a downward slope toward the molten metal spout is formed and after laying the engagement and furnace bottom of the jig for lifting the said slit Bok general bottom part blocks slit Bok is open in the operational side, extracting the lifting jig, embedding the slit Bok in monolithic refractories A method of constructing a ladle hearth bottom , characterized by returning .

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